Travelers planning a trip to, from, or within Europe on October 10 may face massive cancellations that day. The Air Traffic Controllers European Unions Coordination is calling on its members to take part in a pan-European job action on 10 October to protect European Commission plans to merge air-traffic control services across the European Union.

The group, which was created in 1989, is an umbrella organization for 28 trade unions that represent more than 14,000 air-traffic controllers on the European continent....